1. Field of the Invention
This invention relates to socket wrenches having a ratcheting function and, more particularly, to a ratchet wrench characterized by short, thin-walled hollow sockets, and a relatively thin handle having a cylindrical opening in which a socket is releasably maintained. A pawl supported within the handle and extending into the opening engages and applies rotational torque directly to a peripheral surface of a socket.
2. Description of the Prior Art
Ratchet wrenches have long been used where bolts and nuts must be installed and removed in machines and equipment of various description. Socket kits or sets usually include a ratchet wrench, various adapters, accessories and attachments, and a plurality of sockets used interchangeably with the ratchet wrench. The usual ratchet wrench comprises a drive handle having a square driving lug which fits into a square opening in one end of a socket which, for example, may constitute a 1/4", 3/8" or 1/2" square lug drive. At the other end the socket has an opening, usually hexagonal, for engagement with a correspondingly sized fastener, such as a nut or head of a bolt. The hexagonal openings range in size from 3/8" to 11/8" in sixteenth inch intervals. The driving lug conventionally has a spring-loaded ball that engages a recess formed in the square socket opening for keeping the wrench and socket in releasable operative engagement.
The head end of wrenches in current use includes a housing which receives a rotating drum carrying the lug drive and is provided with external splines for engagement by a ratchet pawl, the position of which determines the direction of drive rotation of the lug. The pawl is operated by manipulating a pin or lever to selectively engage and disengage the pawl to and from the drum splines and facilitate rotation of the lug drive in either a clockwise or counterclockwise direction.
The lug drive is integral with and projects outwardly from the rotating drum, and sockets of various sizes having drive apertures dimensioned to receive the lug are fitted to the lug drive and seat against the drum. Accordingly, to accommodate a ratchet wrench of this type, the work space must be at least as wide as the length of the socket, which may be about two inches for a socket with a standard 3/4" drive opening, plus the width of the wrench housing. In many situations, for example the cramped quarters of an automobile engine, the work space will not permit access of conventional ratchet wrenches because of the combined thickness of the housing and socket.
It is an object of this invention to provide a ratchet wrench system which has an effective work thickness much less than that of the wrench housing, lug drive and socket combination of a conventional wrench of comparable size.
Another object of this invention is to provide a low-profile ratchet wrench that is smaller and lighter in weight than a conventional wrench of comparable fastener size and strength.
Another object of the invention is to provide a ratchet wrench wherein a portion of the length of the socket is received in a cylindrical opening extending through the wrench handle, thereby to reduce the overall thickness of the system and enable the handle to apply rotational torque to an exterior surface of the received portion of the socket.
Another object is to provide a ratchet wrench system wherein the handle has the capability of magnetically picking up a socket of any size at arms length.
Still another object of the invention is to provide a ratchet wrench system having thin-walled sockets which have an axial opening sufficiently large to allow a bolt engaged by a fastener of a size corresponding to the fastener opening of the socket to pass through the axial opening and extend beyond the nut.
The described low-profile advantage, and others of the above objects, are achieved in the ratchet wrench system described in Applicant's U.S. Pat. No. 5,857,390, dated Jan. 12, 1999, which comprises a wrench handle and a plurality of interchangeable hollow, thin-walled sockets. A portion of the length of a socket is received in a circular opening extending through the wrench handle, and a resilient steel spring supported in a circumferential groove formed in the wall of the circular opening engages a circumferential groove on an outer surface of the received portion of the socket for maintaining the handle and socket in easily releasable operative engagement.
While this patented wrench system is enjoying commercial acceptance, with the spring and groove detent mechanism performing satisfactorily, the requirement for a circumferential groove on the peripheral surface of each socket and also in the wall of the cylindrical opening, and the fabrication and the assembly of the resilient spring, complicate the manufacture of an otherwise straightforward product, with attendant increase in cost.
Accordingly, a more specific object of the invention is to provide alternative, less costly means for maintaining the socket in operative engagement with the wrench while permitting its easy removal.